Prepare the dressing. Combine olive oil, white wine vinegar, shallots, honey, mustard, garlic, salt, pepper and blueberries in a jar. Using an immersion blender, blend the ingredients until smooth (you can also use a mini-chopper).

In a large bowl, combine spinach, avocado, and nectarine, blueberries, red onion, and walnuts. When ready to serve, toss with dressing.